Your electrical system is flickering. Maybe a loose battery connection, a failing battery/charging system, or it maybe an ECU malfunction. Try reflashing your system with the same tune if you can, but I would start out by disconnecting the battery and doing a hard reset of all the electrical systems. But just remember that if the problem consists, really try and find the exact cause, because one time the systems might go off and not come back on, then you've got a very fun scenario, since all of the systems are fly-by-wire (run by the electrical system). But it sounds like a loose connection close to the battery, an ECU malfunction, or a failing battery or charging system. And also, don't trust the gauges on your dash except for maybe the temperature sensor, since the secondary motors that drive the needles in the small gauges are notorious for malfunctions, and can read the same whether your battery is dead or new in some cases.